Experts on melanoma--a type of skin cancer--from the Melanoma Prevention Working Group recently authored a paper summarizing current research into both drugs and natural products that prevent melanoma. They name several of these as candidates to enter phase 3 clinical trials in the next 5 years. Two of these experts are researchers at Huntsman Cancer Institute: Tawnya L. Bowles and Douglas Grossman.

As we've discussed in the past, phase 3 clinical trials come very late in the process of drug development, and constitute one of the final steps before the FDA makes a decision whether to approve a drug for use in the United States.

The prevention techniques listed in the paper don't just prevent melanoma from forming. Primary chemoprevention can do that, or it can help repair mutations in still-normal (not yet cancerous) cells. Secondary chemoprevention slows, blocks, or reverses the advance of precancerous cells to cancerous cells. Tertiary chemoprevention impedes melanoma from recurring in patients who have already had the disease. The paper focuses on primary and secondary chemoprevention methods.

10 agents are currently being studied, including sunscreen, vitamins E and D, and various drugs. Sunscreen is the current number one choice for prevention of skin cancer and scientists know it works. The tests being done right now are just on different combinations of ingredients. Vitamin E creams are suspected to be helpful in combination with vitamin C.

Of these 10 agents, the working group's experts list five as having high or moderately high potential to become important in hospital settings in the near term--entering phase 3 clinical trials in the next 5 years.

Moderately high

• An enzyme is a chemical produced by a living thing that functions to make certain chemical reactions happen--not incredibly unlike the way that turning your car key makes the engine start.
• There is some evidence that two specific enzymes can repair damage to DNA and reduce the risk of developing melanoma.

• Nicotinamide is a form of vitamin B. It's found in food and commonly used as a dietary supplement.
• Some studies have found that it decreases the rate of cell division (remember that out of control cell division is what makes tumors). There is also evident that it may help repair DNA damage. However, other studies suggested it might make melanoma spread more aggressively. Future research will have to answer this question.

• Acetylsalicylic acid is the scientific name for a drug you'll probably find familiar: aspirin. Aspirin and other NSAIDs (non-steroidal anti-inflammatory drugs) are common over the counter drugs used to treat an incredible variety of diseases and symptoms, from alleviating pain and fevers to reducing the risk of heart attack.
• In studies of mice, it delays development of melanoma after they've been exposed to UV rays. Other studies in humans suggest it might help prevent skin cancers. However, it may contribute to increased spread of melanoma that already exists. Future research will have to address this concern.

• Silibinin is one ingredient in milk thistle extract. Current medical uses are treatment of toxic liver damage such as that resulting from poisonings.
• It has been tested in many animal models of cancer, including grafts of human cancer into mice, and is believed to reduce the growth of cancer cells.

High

• EGCG is short for epigallcatechin-3-gallate. Try to say that five times fast. Despite the intimidating name, the chemical is found in green and black teas. It is present in drugs currently used for the treatment of genital warts.
• Many studies suggest that ingestion or use of the chemical on the skin as a creme may have anticancer effects.

Melanoma isn't particularly common, accounting for only about 1% of all skin cancers. However, it is the most deadly form of skin cancer and it has become increasingly more common over the last 30 years. Utah has the highest rates of melanoma in the country, making the disease a special concern at Huntsman Cancer Institute.

What all this means is that there is hope on the horizon for those at risk of developing melanoma--new options may arise that will help prevent the disease.

Sources

Jeter, J., Bowles, T., Curiel-Lewandrowski, C., Swetter, S., Filipp, F., Abdel-Malek, Z., . . . Cassidy, P. (2018). Chemoprevention agents for melanoma: A path forward into phase 3 clinical trials.Cancer,Cancer, 03 October 2018.